Charleston, South Carolina has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 14.6 °C (low) to 23.6 °C (high). Annual precipitation averages 1336.1 Millimeters. Charleston is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Frost Rare through the first frost around Frost Rare.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 4.7 °C | 14.9 °C | 80.26 mm |
| February | 5.8 °C | 16.3 °C | 82.04 mm |
| March | 9.4 °C | 19.6 °C | 86.11 mm |
| April | 13.6 °C | 23.2 °C | 82.55 mm |
| May | 18.6 °C | 27 °C | 83.57 mm |
| June | 22.4 °C | 29.9 °C | 148.34 mm |
| July | 24.2 °C | 31.7 °C | 183.39 mm |
| August | 23.7 °C | 31 °C | 176.53 mm |
| September | 21.2 °C | 28.8 °C | 138.68 mm |
| October | 15.7 °C | 24.8 °C | 115.32 mm |
| November | 9.7 °C | 20.1 °C | 69.6 mm |
| December | 6.4 °C | 16.4 °C | 89.66 mm |
| Annual | 14.6 °C | 23.6 °C | 1336.05 mm |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | Frost Rare |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 9a : -6.7°C to -3.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |